Quoting [EMAIL PROTECTED] ([EMAIL PROTECTED]):
>
> >From 8886ef518c1855890be7fbc6bea853ce7feb263e Mon Sep 17 00:00:00 2001
> From: Sukadev Bhattiprolu <[EMAIL PROTECTED]>
> Date: Tue, 9 Sep 2008 18:42:44 -0700
> Subject: [PATCH 08/10] Define get_sb_ref()
>
> See comments in fs/super.c (in patch below) for need for this interface.
> This interface will be used in follow-on patch to enable multiple
> instances of devpts.
>
> Signed-off-by: Sukadev Bhattiprolu <[EMAIL PROTECTED]>
> ---
> fs/super.c | 37 +++++++++++++++++++++++++++++++++++++
> include/linux/fs.h | 2 ++
> 2 files changed, 39 insertions(+), 0 deletions(-)
>
> diff --git a/fs/super.c b/fs/super.c
> index e931ae9..ba7059c 100644
> --- a/fs/super.c
> +++ b/fs/super.c
> @@ -882,6 +882,43 @@ int get_sb_single(struct file_system_type *fs_type,
> }
>
> EXPORT_SYMBOL(get_sb_single);
> +/*
> + * int get_sb_ref(struct super_block *sb, int flags, void *data,
> + struct vfsmount *mnt)
> + *
> + * This interface is needed to support multiple mounts in devpts while
> + * preserving backward compatibility of the current 'single-mount'
> + * semantics i.e all mounts of devpts without the 'newinstance' mount
> + * option should bind to the initial kernel mount, like get_sb_single().
> + * Mounts with 'newinstance' option create a new private namespace.
> + *
> + * But for single-mount semantics, devpts cannot use get_sb_single(),
> + * because get_sb_single()/sget() find and use the super-block from
> + * the most recent mount of devpts. But that recent mount may be a
> + * 'newinstance' mount and get_sb_single() would pick the newinstance
> + * super-block instead of the initial super-block.
> + *
> + * This is a simplified version of get_sb_single() and assumes that
> + * caller has a properly initialized @sb.
> + */
> +int get_sb_ref(struct super_block *sb, int flags, void *data,
> + struct vfsmount *mnt)
> +{
> + int err;
> +
> + spin_lock(&sb_lock);
> +
> + if (!grab_super(sb))
> + return -EAGAIN;
> +
> + err = do_remount_sb(sb, flags, data, 0);
> + if (err) {
> + /* Don't deactivate_super() - its from initial pts mount */
But you did increment sb->s_active, and you're not decrementing it?
> + up_write(&sb->s_umount);
> + return err;
> + }
> + return simple_set_mnt(mnt, sb);
> +}
>
> struct vfsmount *
> vfs_kern_mount(struct file_system_type *type, int flags, const char *name,
> void *data)
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 580b513..3bda46d 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -1512,6 +1512,8 @@ extern int get_sb_single(struct file_system_type
> *fs_type,
> int flags, void *data,
> int (*fill_super)(struct super_block *, void *, int),
> struct vfsmount *mnt);
> +extern int get_sb_ref(struct super_block *sb, int flags, void *data,
> + struct vfsmount *mnt);
> extern int get_sb_nodev(struct file_system_type *fs_type,
> int flags, void *data,
> int (*fill_super)(struct super_block *, void *, int),
> --
> 1.5.2.5
_______________________________________________
Containers mailing list
[EMAIL PROTECTED]
https://lists.linux-foundation.org/mailman/listinfo/containers
_______________________________________________
Devel mailing list
Devel@openvz.org
https://openvz.org/mailman/listinfo/devel
